Bai Jianrong, Yan Meng, Guo Lingchuan, Lei Zhe, Liu Weishuo, Zou Zigui, Li Jiao, Zheng Yushuang
Department of Pathology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China.
Zhongguo Fei Ai Za Zhi. 2025 Jun 20;28(6):441-449. doi: 10.3779/j.issn.1009-3419.2025.101.10.
Primary pulmonary mucoepidermoid carcinoma (PMEC) is an exceedingly rare malignancy originating from bronchial submucosal glands, accounting for <0.2% of lung cancers. Histologically characterized by a triphasic composition of mucinous, epidermoid, and intermediate cells, PMEC is classified into low-grade (favorable prognosis) and high-grade (aggressive behavior) subtypes. This study aimed to investigate the clinicopathological characteristics and prognostic indicators of PMEC.
Clinicopathological, radiological, molecular, and survival data from 26 PMEC patients were retrospectively analyzed, including immunohistochemical profiles and MAML2 rearrangement status, supplemented by literature review.
The cohort comprised 14 males and 12 females (mean age: 55.6 years). Eight patients (30.8%) were smokers, and 19 (73.1%) presented with symptoms. Central tumors predominated (n=19, 73.1%) versus peripheral lesions (n=7, 26.9%). Computed tomography (CT) imaging consistently revealed hypo-to-isodense masses/nodules. Pathologically, 19 cases were low-grade and 7 high-grade. Immunohistochemically, the tumor cells were positive for CK7, P40, P63 and CK5/6, and the Ki-67 index ranged from 2% to 70%. MAML2 rearrangement was detected in 52.4% (11/21) of tested cases. Clinical staging distribution: stage I (n=14), stage II (n=8), stage III (n=3), stage IV (n=1). Treatment modalities: radical surgery alone (n=13), surgery with adjuvant chemotherapy (n=11), chemoradiotherapy (n=1), and conservative management (n=1). With a median follow-up of 57 months, 6 patients (23.1%) died. Prognostic analysis demonstrated: (1) Significantly inferior survival in high-grade versus low-grade groups (P<0.05); (2) Lymph node metastasis, advanced stage, Ki-67>20%, and high-grade histology significantly correlated with reduced overall survival (P<0.05); (3) Lymph node metastasis constituted an independent poor prognostic factor (HR=12.73, 95%CI: 1.22-132.96).
PMEC exhibits distinct clinicopathological features, with MAML2 rearrangement present in approximately half of cases. Lymph node metastasis, advanced stage, high Ki-67 proliferation index, and high-grade histology are key determinants of poor prognosis, with lymph node metastasis serving as an independent risk factor.
原发性肺黏液表皮样癌（PMEC）是一种极为罕见的起源于支气管黏膜下腺的恶性肿瘤，占肺癌的比例不到0.2%。PMEC在组织学上的特征是由黏液细胞、表皮样细胞和中间细胞组成的三相结构，分为低级别（预后良好）和高级别（侵袭性）亚型。本研究旨在探讨PMEC的临床病理特征和预后指标。
回顾性分析26例PMEC患者的临床病理、放射学、分子和生存数据，包括免疫组化特征和MAML2重排状态，并辅以文献复习。
该队列包括14例男性和12例女性（平均年龄：55.6岁）。8例患者（30.8%）为吸烟者，19例（73.1%）有症状。中央型肿瘤为主（n=19，73.1%），而周围型病变较少（n=7，26.9%）。计算机断层扫描（CT）成像始终显示为低密度至等密度肿块/结节。病理上，19例为低级别，7例为高级别。免疫组化显示，肿瘤细胞CK7、P40、P63和CK5/6呈阳性，Ki-67指数范围为2%至70%。在52.4%（11/21）的检测病例中检测到MAML2重排。临床分期分布：I期（n=14），II期（n=8），III期（n=3），IV期（n=1）。治疗方式：单纯根治性手术（n=13），手术加辅助化疗（n=11），放化疗（n=1），以及保守治疗（n=1）。中位随访57个月，6例患者（23.1%）死亡。预后分析表明：（1）高级别组的生存率明显低于低级别组（P<0.05）；（2）淋巴结转移、晚期、Ki-67>20%和高级别组织学与总生存期缩短显著相关（P<0.05）；（3）淋巴结转移是独立的不良预后因素（HR=12.73，95%CI：1.22-132.96）。
PMEC具有独特的临床病理特征，约半数病例存在MAML2重排。淋巴结转移、晚期、高Ki-67增殖指数和高级别组织学是预后不良的关键决定因素，淋巴结转移是独立的危险因素。
